US6959830B1 - Metal container with thread - Google Patents

Abstract

A metal container with thread capable of preventing such a defect that the strength of a lower end of a mouth part and an upper end of a shoulder part of a container main body is non-resistant to a pressing force in radial and axial directions, and a part of the container may be collapsed or buckled during a capping operation where content is filled into the container and cap is fitted to the container automatically by a machine, characterized in that at least one or more inwardly curving smooth annular recessed parts(4) and at least one or more outwardly curving smooth annular projected parts(5) are formed in an area ranging from the lower end (2a) of the mouth part(2) of the container main body to around the upper end(3a) of a tapered shoulder part increasing gradually in radial direction.

Description

TECHNICAL FIELD

The present invention relates to a metal container with thread in which a mouth part including a threaded part and an upper end of a shoulder part have an improved strength. The present invention further relates to a metal container with thread capable of maintaining a highly airtight condition.

BACKGROUND ART

Conventionally, a metal container with thread, as shown inFIG. 19, is manufactured by drawing, drawing-and-ironing or impact forming from a metallic material such as aluminium. An open mouth part of such a metal container is closed airtight, as a cap is screwed on a threaded part formed in a periphery of the cylindrical mouth part.FIG. 19 is a cross sectional view of a conventional metal container with thread. Denoted at50 is a container main body, and the containermain body50 is formed by acurled part51, amouth part52 with a threaded part, atapered shoulder part53, atrunk part54 and abottom part55, shown in this order from the top. A female screw of acap56 and a male screw of themouth part52 are fitted with each other, whereby themouth part52 of the containermain body50 is sealed up. Thesymbol57 denotes packing. In such a containermain body50, as shown inFIG. 20, theshoulder part53 is formed to have a linear cross sectional shape up to itsupper end53a, and theupper end53aof theshoulder part53 is continuous up to alower end52aof the mouth part.

Meanwhile, a metal container with thread as shown inFIG. 21 is known and commercially available, where plurality of protruded parts62 (three inFIG. 21) are formed at schematic equal intervals entirely over ashoulder part61 of a containermain body60.

However, as shown inFIG. 20, the containermain body50 shown inFIG. 19 has a problem that the strength of thelower end52aof themouth part52 and theupper end53a(area W) of theshoulder part53 is weak against pressure forces in a radial direction and an axial direction (pressing forces P, Q) therefore, the area W may be collapsed or buckled during a capping operation to fill content into the container and fit a cap to the container automatically using a machine.

With respect to the containermain body60 shown inFIG. 21, a purpose of forming the plurality ofprotruded parts62 entirely over theshoulder part61 is to mainly achieve a design effect of the metal container with thread and to prevent theshoulder part61 from getting wrinkled during a necking operation of manufacturing steps. Thus, an improvement in strength at the mouth part and the upper edge of the shoulder part is not intended here, accordingly no actual enhancement of strength is expected.

On the other hand, as shown inFIG. 22, thecurled part51 is formed at the upper end of themouth part52 in the conventional metal container with thread to thereby ensure a better strength, safety for a user and sealable effect. In other words, by means of an axial clamping force developed as the female screw of thecap56 is fitted to the male screw of themouth part52, thepacking57 laid on an inner ceiling surface of thecap56 abuts on a top surface of thecurled part51 formed at the upper end of themouth part52, whereby an opening at themouth part52 is sealed up. Alower end56aof thecap56 is bent along a bead part (annular groove)52bformed in themouth part52 and fitted with the upper area of the bead part to its end.

However, since thepacking57 and the ceiling surface of thecurled part51 are in surface contact, such a dosing structure has a problem with a sealing capability if thecurled part51 has a slight dimensional error and the surface contact is accordingly weak. In short, when content develops an internal pressure, the content may leak out between thepacking57 and the ceiling surface of thecurled part51. Particularly, as for a metal container containing, a carbonated beverage such as beer and cola, it is required that the metal container is sealed up without fail again after opened once, do that the quality and the internal pressure of the remaining contained drink are maintained, so that an insufficient sealing capability becomes a problem.

An attempt to improve a sealing capability by strongly tightening thecap56 and increasing applied pressure between thepacking57 and thecurled part51 to one another invites the area W at the upper end of theshoulder part53 shown inFIG. 20 to twist more, and therefore, makes it easier for the area W to be buckled. If the tightening force is reduced to prevent such buckling, leakage tends to occur.

On the other hand, in a conventional metal container, an area of thebead part52beasily collapses whenlower end56aof thecap56 is plastically deformed along thebead part52bin the manner as shown inFIG. 22. Further, thecap56 may be a screw cap with preformed thread or a roll-on type cap put on themouth part52 to be pressurized along the male screw of the mouth part to thereby form threads. In the latter case, a side wall of thecap56 is pressed strongly in the radial direction toward inside, and therefore, the threaded part may easily collapse.

In addition, where the metal container shown inFIG. 19 uses a cap such as a Pilfer Proof cap (PP cap) and a similar Alten cap (also known as a flavor cap a high-lock cap), to be fractured as opened in order to clearly indicate a user that the container has been unopened, the threaded part, the bead part and the like collapse more easily and the upper end of the shoulder part buckles more easily, since the strength of the cap is high.

The present invention was made in view of the conventional problems described above, and accordingly, a first object of the present invention is to provide a metal container with the threadedpart52 and thelower end52aof the mouth part as well as theupper end53a(area W) of theshoulder part53 having an improved strength in a radial direction and an axial direction. Further, a second object of the present invention is to provide a metal container with thread capable of maintaining a highly airtight condition.

DISCLOSURE OF THE INVENTION

A metal container with thread according to the present invention is manufactured by drawing, drawing-and-ironing or impact forming from a metallic material with container main body consisting of a mouth part including a threaded part, a tapered shoulder part, a trunk part and a bottom part and maintaining a highly airtight condition with a cap screwed on, and is characterized in that at least one or more inwardly curving smooth annular recessed parts or at least one or more outwardly curving smooth annular protruded parts are formed around an upper end of said tapered shoulder part widening in a radial direction toward below from a lower end of said mouth part. According to a preferred embodiment, both said annular protruded parts and annular recessed parts are formed. Further, a bead part for bending a lower end of said cap for engagement may be formed in the vicinity of said lower end of said mouth part.

A metal container with thread according to a second aspect of the present invention is manufactured by drawing, drawing-and-ironing or impact forming from a metallic material with container main body consisting of a mouth part including a threaded part, a tapered shoulder part, a trunk part and a bottom part and maintaining a highly airtight condition with a cap screwed on, and is characterized in that an annular rounded projection with a rounded radius of 0.2 to 0.8 mm is formed at an upper end of the mouth part so that when the cap is screwed on, the annular projection bites into packing laid on an inner surface of a ceiling surface of the cap and an air tight condition is realized.

A third aspect of the present invention is characterized in that curled part with sectional view of circle around upper end of said mouth part is formed and flat surface around outer part of this curled part is formed, thereby creating outer part of the curled part with sectional view of a straight line and inner part of the curled part with sectional view of an arc continuously around upper end of mouth part, and a bent line which appears between the outer part and inner part of upper end of the curled part forms an annular slightly rounded projection.

Fourth aspect of the present invention is characterized in that curled part with sectional view of circle around upper end of said mouth part is formed and flat surface around inner part of the curled part is formed, thereby creating inner part of curled part with sectional view of straight line and outer part of curled part with sectional view of an arc, and a bent line which appears between the outer part and inner part of upper end of the curled part forms an annular slightly rounded projection.

The container main body may be formed by integral forming so that the mouth part including the threaded part, the tapered shoulder part, the trunk part and the bottom part are integral with each other, or alternatively, the mouth part including the threaded part and a tapered neck part may be formed integral with each other to thereby form an upper container body, the side wall part and the bottom part may be formed integral with each other to thereby form a lower container body, and the upper container body and the lower container body may be joined to each other.

A fifth aspect of the present invention manufactured by drawing, drawing-and-ironing or impact forming from a metallic material; comprising container main body consisting of a mouth part including a threaded part, a tapered shoulder part, a trunk part and a bottom part; a cap which screws to the mouth part of container main body; and a packing housed inside a ceiling surface of the cap and held between ceiling surface of the cap and upper end of the mouth part, and by forming a flat surface at outer part of the curled part, a bent line to form an annular slightly rounded projection annularly between the inner part and the outer part of the upper end of the curled part is formed, and upper-side of the cap is crimped until flat surface around outer part of the curled part and packing housed inside a ceiling surface of the cap abuts each other.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front cross sectional view showing a first preferred embodiment of the present invention;

FIG. 2 is a cross sectional view showing a mouth part and an upper end of a shoulder part according to the first preferred embodiment of the present invention;

FIG. 3 is an enlarged cross sectional view showing an area A according to the first preferred embodiment of the present invention;

FIG. 4 is a cross sectional view showing a mouth part and an upper end of a shoulder part according to a second preferred embodiment of the present invention;

FIG. 5 is a cross sectional view showing a mouth part and an upper end of a shoulder part according to a third preferred embodiment of the present invention;

FIG. 6 is a cross sectional view showing a mouth part and an upper end of a shoulder part according to a fourth preferred embodiment of the present invention;

FIG. 7 is an elevational view showing a crush strength test on a bead part of a metal container with thread according to the present invention;

FIG. 8 is an elevational view showing a crush strength test on a threaded part of a metal container with thread according to the present invention;

FIG. 9 is an elevational view showing a buckling strength test on a shoulder part of a metal container with thread according to the present invention;

FIG. 10 is an elevational view showing a metal container with thread according to the present invention forming a mouth part, a shoulder part, a side wall part and a bottom part integrally with each other;

FIG. 11 is an enlarged cross sectional view showing a mouth part having a threaded part of a metal container with thread according to a fifth preferred embodiment of the present invention;

FIG. 12 is a cross sectional view showing a condition that a cap is screwed on the mouth part of the metal container with thread according to the fifth preferred embodiment of the present invention;

FIG. 13 is a flow chart showing a method of attaching the cap to the mouth part of the metal container with thread according to the fifth preferred embodiment of the present invention;

FIG. 14 is a cross sectional view showing a condition that a cap is screwed on a mouth part of a metal container with thread according to a sixth preferred embodiment of the present invention;

FIG. 15 is a cross sectional view showing a condition that a cap is screwed on a mouth part of a metal container with thread according to a seventh preferred embodiment of the present invention;

FIG. 16 is a cross sectional view showing a condition that a cap is screwed on a mouth part of a metal container with thread according to an eighth preferred embodiment of the present invention;

FIG. 17 is a elevational view showing manufacturing of the metal container with thread according to the fifth preferred embodiment shown inFIG. 10;

FIG. 18 is a partial cross sectional elevational view showing a metal container with thread according to other embodiment of the present invention which is obtained by bonding an upper container body to a lower container body;

FIG. 19 is a cross sectional view showing an example of a conventional metal container with thread;

FIG. 20 is a cross sectional view showing a mouth part and an upper end of a shoulder part of the metal container with thread which is shown inFIG. 19;

FIG. 21 is a elevational view showing other example of a conventional metal container with thread;

FIG. 22 is an enlarged cross sectional view showing a condition that a cap is screwed on a mouth part of a conventional metal container with thread.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 through 3 show a metal container with thread according to a first preferred embodiment of the present invention. A containermain body1 of this container with thread is basically approximately the same as the conventional one, and as shown inFIG. 1, comprises acylindrical mouth part2, atapered shoulder part3 downwardly contiguous from alower end2aof themouth part2, atrunk part11 contiguous from a lower end of the shoulder part, and abottom part12 closing a lower end of thetrunk part11. As clearly shown inFIG. 2, a characteristic is that an inwardly curving smooth annularrecessed part4 is formed in an area around anupper end3aof the shoulder part3 (area A) and below this an outwardly curving smooth annularprotruded part5 is formed contiguously. A lower portion of theprotruded part5 is linearly continuous, like conventional ones. A portion in the vicinity of an upper end of themouth part2 has a slightly smaller diameter, and a curledpart13 curled up outwardly is formed at this upper end.FIG. 3 is a cross sectional view further enlarging the area A according to the first preferred embodiment.

The containermain body1 is obtained by drawing, drawing-and-ironing or impact forming a metallic material, such as aluminium for instance, into a cylindrical shape with bottom, thereafter forming the shoulder part and the mouth part by shoulder-drawing, abead part2bby rolling, then a threaded part, and further the curledpart13 at the upper end of the mouth part by curling part. In this embodiment, an upper portion of the containermain body1 including themouth part2 with theshoulder part3 and a lower portion including thebottom part12 are formed integral with each other.

The diameter of themouth part2 is approximately 35 to 40 mm, for instance, preferably about 37.8 mm, while the diameter of thetrunk part11 is approximately 60 to 70 mm, preferably about 66.0 to 66.4 mm. The thickness of a material plate is approximately 0.2 to 0.3 mm, for example, preferably about 0.21 to 0.25 mm. The plate thickness of themouth part2 after forming is approximately 0.3 to 0.4 mm, preferably about 0.31 to 0.35 mm. The angle β of theshoulder part3 is approximately 25 to 30 degrees with respect to a perpendicular line X as shown inFIG. 1. The plate thickness of theshoulder part3 is around 0.30 to 0.34 mm in the vicinity of theupper end3a. Meanwhile, the plate thickness of thetrunk part11 is about 0.11 to 0.15 mm, for instance. The plate thickness of the curledpart13 is approximately 0.33 to 0.37 mm.

As shown inFIG. 2, a corrugatedmale screw14 is formed by rolling and otherwise at themouth part2. The thread diameter of themale screw14 is about 36.9 to 37.5 mm. Askirt part16 with somewhat larger diameter is formed in a lower part of themouth part2, and thebead part2bis formed below continuously. Thebead part2bis an annular groove and almost trapezoidal in cross section. Theskirt part16 and anupper wall17aof thebead part2bare, as described later, for caulking a lower end of a cap to be fractured to open, such as a Pilfer Proof cap and an Alten cap (SeeFIG. 13).

As shown inFIG. 3, alower wall17bof thebead part2bis smoothly curved to be contiguous to thelower end2aof the cylindrical mouth part, and the annular recessedpart4 is downwardly contiguous from theupper end3aof the contiguous shoulder part to thelower end2a. The recessedpart4, in its cross section, preferably has a radius of curvature R of about 0.5 to 5 mm, and more preferably, approximately 2 to 4 mm. The angle of inclination (i.e., the degree of curve) θ of a common tangent line K of the recessedpart4 and theprotruded part5 is preferably about 35 to 60 degrees, and more preferably, approximately 40 to 50 degrees.

FIG. 4 shows a metal container with thread according to a second preferred embodiment of the present invention. The containermain body1 of this metal container is characterized in that one inwardly curving smooth recessedpart6 is formed in a portion around theupper end3aof the shoulder part (area B). Theprotruded part5 ofFIG. 3 is not formed. Thelower wall17bof thebead part2bis contiguous to the upper end of theshoulder part3 while remaining inclined, and the recessedpart6 is formed somewhat below this. The recessedpart6 preferably has approximately the same radius of curvature, width and depth as the recessedpart4 according to the first preferred embodiment shown inFIG. 3.

FIG. 5 shows a metal container with thread according to a third preferred embodiment of the present invention. The containermain body1 of this metal container is characterized in that one outwardly curving smooth protrudedpart7 is formed in a portion around theupper end3aof the shoulder part3 (area C) continuous to thelower end2aof the mouth part. No recessed part is formed. Theprotruded part7 preferably has approximately the same cross sectional shape and angle of gradient (i.e., the degree of curve) as theprotruded part5 according to the first preferred embodiment.

FIG. 6 shows a metal container with thread according to a fourth preferred embodiment of the present invention. The containermain body1 of this metal container is characterized in that an inwardly curving smooth recessedpart8 is formed in a portion around theupper end3aof the shoulder part3 (area D) continuing to thelower end2aof the mouth part, and continuously an outwardly curving smooth protrudedpart9 is formed, and further continuously an inwardly curving smooth recessedpart10 is formed. In other words, the two recessedparts8 and10 and one protrudedpart9 are formed alternately in the area D. As another preferred embodiment, two recessed parts and two protruded parts may be formed alternately (not shown).

Next, an effect of the metal containers with thread above is described. In the metal containers with thread according to the first to the fourth preferred embodiments, since the areas A, B, C and D are each bent to form the recessed parts and/or the protruded parts, the strength against pressing forces P and Q respectively in a radial direction and an axial direction improves. The radius of curvature R and the angle of inclination θ of the recessed parts and/or the protruded parts may be larger than the ranges described above. In the case that these values are larger, however, the strength against the pressing force P in the radial direction is stronger, while the strength against the pressing force Q in the axial direction is weaker. Hence, to improve in strength against both the pressing forces P and Q, the recessed parts described above preferably have the radius of curvature R of about 0.5 to 5 mm and the angle of θ of about 35 to 60 degrees.

Embodiment

The following describes test results comparing the strength of the mouth part and the upper end of the shoulder part between the metal container with thread comprising the recessedpart4 and the protruded part5 (Embodiment) according to the first preferred embodiment of the present invention and a conventional metal container with thread not comprising a recessed part or a protruded part (Comparison).FIG. 7 shows a test for measuring a crush condition of thebead part2bof themouth part2 when pressurized with a pressing force F1 from above,FIG. 8 shows a test for measuring a crush condition of the threaded part when pressurized themouth part2 from above with a pressing force F2, andFIG. 9 shows a test for measuring a buckling strength when pressurized the upper end of themouth2 from above in the axial direction with a pressing force F3.

Test Condition

The outer diameter of the container: 66 mmø. The height of the container: 166 mm. The outer diameter of the mouth part: 37.8 mmø. The thickness of the threaded part and the bead part: 0.32 mm. The thickness of the lower end of the shoulder part: 0.2 mm. The thickness of the trunk of the container: 0.15 mm. The test results are as shown in Table 1.

TABLE 1
The number of testing n = 2

	Crush Strength of	Crush Strength of	Buckling Strength
	Bead Part (N)	Threaded Part (N)	of Shoulder Part (N)

Comparison	113	137	1451
Embodiment	167	142	1657

From the test results above, it is found that with respect to the metal containers with thread according to the present invention, the crush strength of the bead part improves 47.8%, the crush strength of the threaded part improves 3.6% and the buckling strength of the shoulder part improves 14.2%.

As described above, the present invention has an effect to improve the strength in an area around the mouth part of the metal container with thread, and particularly in an area from the lower end of the threaded part to the upper end of the shoulder part.

Next, a second aspect of the present invention is described with reference to the associated drawings.FIGS. 10 to 12 show a fifth preferred embodiment of the present invention, and acap18 to cover themouth part2 is illustrated in an upper portion of the containermain body1 therein. Thecap18 has a cylindrical shape with bottom, and afemale screw19 to engage with the threaded part of themouth part2 is formed in a peripheral wall. Thecap18 is a so-called Pilfer Proof cap. Other caps to be broken as opened, such as an Alten cap, may be used instead.

A characteristic of the fifth preferred embodiment is that anannular projection13ais formed at the upper end of themouth part2 of the containermain body1 as shown inFIGS. 11 and 12. Other configurations are substantially the same as those shown inFIG. 1, and therefore, the same portions is denoted at the same reference symbols and is not described. In order to form theprojection13aat the outer upper end of themouth part2, first, the curledpart13 in circular-shaped cross section is formed by a normal method, such as press work using a curling die, at the upper end of themouth part2, acore22 is inserted inside the containermain body1 as shown inFIG. 17, and then an outer circumferential surface of the curledpart13 is crushed with aroll23 abutting on the curledpart13 from the outward side to thereby form aflat surface part13bon the cylindrical surface approximately in parallel to the central axis of the containermain body1. As a result, as shown inFIG. 11, theprojection13ais created at an intersection of an innercircumferential surface13cand theflat surface part13bof the curledpart13 as it originally has a circular shape in cross section, i.e., along a bent line outside the upper end. Theprojection13ais loosely curved (over about 0.2 to 0.8 mm).

In order to attach thecap18 of the Pilfer Proof type to the containermain body1 manufactured in this manner, first, as denoted at a capping step S1 shown inFIG. 13, thecap18 is screwed on themouth part2 of the containermain body1. In this condition, the upper end at the outer periphery of thecap18 is cylindrical without any stepped area created. Meanwhile, the lower end remains directly downward. Further, in this condition, there is a gap between theflat surface part13bof the curledpart13 and the inner circumferential surface of thecap18, and an outer circumferential part24aof packing24 fit inside a ceiling surface of thecap18 expands sidewise. This however realizes a high sealable effect, since theprojection13abites into the packing24.

Following this, as denoted at a caulking step S2 shown inFIG. 13, anupper end18aat the outer periphery of thecap18 is pressurized inwardly in the radial direction, to thereby form an annular stepped part. This makes the outer circumferential part24aof packing24 bent downward and held between theflat surface part13band an inner surface of the annular stepped part. This further enhances the sealable effect. Further, alower end18bof the cap is bent inwardly and pressed against theupper wall17aof thebead part2b. Thecap18 is consequently fit so as not to be removed unless broken.

According to a sixth preferred embodiment shown inFIG. 14, a curledpart15 is applied crushing so as to be inclined at a certain angle with respect to the central axis of the containermain body1, and aflat surface part15bis accordingly created. At an intersection of theflat surface part15band the curledpart15, approximately right above the curledpart15, aprojection15ais formed. Theprojection15ais loosely curved (with a radius of about 0.2 to 0.8 mm).

According to a seventh preferred embodiment shown inFIG. 15, after forming aflat surface part25bwith a cylindrical surface at an outer periphery of the curledpart25 to be approximately parallel to the central axis of the containermain body1, aflat surface part25cinclined at a certain angle is further formed on theflat surface part25b. Due to this, aprojection25ais created at an intersection of theflat surface part25cand the curledpart25, approximately right above the curledpart25. Theprojection25ais loosely curved (with a radius of about 0.2 to 0.8 mm). The inclinedflat surface part25cdescribed above has a three-dimensional conical shape in reality.

Further, according to an eighth preferred embodiment shown inFIG. 16, crushing applied to a curledpart35 is executed on the opposite side of the first preferred embodiment, namely, the inward side of the containermain body1, so that aflat surface part35bis formed on the inward side of the curledpart35. Hence, aprojection35ais created at an inward upper end. Theprojection35ais loosely curved (with a radius of about 0.2 to 0.8 mm).

In any one of the preferred embodiments described above, the containermain body1 is formed as integrated one unit. However, the present invention is not limited to this. The container main body can be created by joining two or more components. The containermain body1 of the metal container with thread shown inFIG. 18 is manufactured as separate units, anupper container body1acomprising themouth part2 and theshoulder part3 formed integral with each other and alower container body1bcomprising thetrunk part11 and thebottom part12 formed integral with each other. A cylindrical joint part3bfor capping an upper end of thetrunk part11 extends at the lower end of theshoulder part3. After forming the respective components, the joint part3bis put on the upper end of thetrunk part11 and adhered with an adhesive or the like, whereby the containermain body1 is manufactured as one integrated unit. As for theupper container body1a, typically, after forming theupper container body1ainto an upside-down cylindrical shape with bottom, theshoulder part3 and themouth part2 are drawn, the upper end of the mouth part is then punched through to create an opening, and the bead part, the threaded part and the curledpart13 are thereafter formed in a manner similar to the above described. Hence, themouth part2 is relatively thick and has a high strength. Forming of the annular projection at the upper end of the curledpart13 and a method of the forming, etc. are the same as in the preferred embodiments described above.

Next, an effect of the seal structure above is described. In the metal containers with thread described above, since the curledparts13,15,25 and35 are created and processed to form the respectiveflat surface parts13b,15b,25b,25cand35bas well as theprojections13a,15a,25aand35aat the intersections of the curled parts and the flat surface parts, when thecap18 is screwed on the threaded part of themouth part2 of the containermain body1, theprojections13a,15a,25aand35abite and fit into the packing24 laid inside the ceiling surface of thecap18. As a result, the opening of themouth part2 of the containermain body1 is sealed up without fail. In other words, at the positions where theprojections13a,15a,25aand35abite into the packing24, theprojections13a,15a,25a,35areliably serve as annular seal points. As thecap18 is screwed and clamps, themouth part2 of the containermain body1 is sealed up tightly. Hence, even if content is a beverage with an internal pressure, such as beer and cola, etc. it is possible to maintain the quality and the internal pressure of the leftover.

As described above, the present invention has an effect to prevent leakage of content at the mouth part and maintain the quality and the internal pressure of a leftover beverage without fail. In addition, since a highly airtight condition is ensured, the cap need not be tightened too strong during a capping operation, so that it is possible to prevent the shoulder part and the like of the container main body from buckling and deformation.

Claims (5)

1. A metal container with thread manufactured by drawing, drawing-and-ironing or impact forming from a metallic material, having a container main body consisting of a mouth part with a threaded part, a tapered shoulder part, a trunk part and a bottom part and maintaining a highly airtight condition with a cap screwed on,

characterized in that only one inwardly curving smooth annular recessed part is formed around an upper end of said smooth tapered shoulder part widening in a radial direction toward below from a lower end of said mouth part,

wherein a bead part for bending a lower end of said cap for engagement is formed in the vicinity of said lower end of said mouth part, the bead part being an annular groove having an almost trapezoidal cross-sectional configuration, and

wherein the inwardly curving smooth annular recessed part has a tangent line at its lowest end at an angle of inclination relative to a perpendicular reference line of approximately 35 to 60 degrees.

2. A metal container with thread manufactured by drawing, drawing-and-ironing or impact forming from a metallic material, having a container main body consisting of a mouth part with a threaded part, a tapered shoulder part, a trunk part and a bottom part and maintaining a highly airtight condition with a cap screwed on,

characterized in that only one inwardly curving smooth annular recessed part and only one outwardly curving smooth annular protruded part are formed around an upper end of said smooth tapered shoulder part widening in a radial direction toward below from a lower end of said mouth part,

wherein a bead part for bending a lower end of said cap for engagement is formed in the vicinity of said lower end of said mouth part, the bead part being an annular groove having an almost trapezoidal cross-sectional configuration, and

wherein the inwardly curving smooth annular recessed part and the outwardly curving smooth annular protruded part has a common tangent line at an angle of inclination relative to a perpendicular reference line of approximately 35 to 60 degrees.

3. A metal container with thread manufactured by drawing, drawing-and-ironing or impact forming from a metallic material, having a container main body consisting of a mouth part with a threaded part, a tapered shoulder part, a trunk part and a bottom part and maintaining a highly airtight condition with a cap screwed on,

characterized in that only one inwardly curving smooth annular recessed part is formed around an upper end of said smooth tapered shoulder part widening in a radial direction toward below from a lower end of said mouth part,

wherein a bead part for bending a lower end of said cap for engagement is formed in the vicinity of said lower end of said mouth part, the bead part being an annular groove having an almost trapezoidal cross-sectional configuration, and

wherein the inwardly curving smooth annular recessed part has a radius of curvature in a range of approximately 0.5 mm to 5.0 mm and a tangent line at its lowest end at an angle of inclination relative to a perpendicular reference line of approximately 35 to 60 degrees.

4. A metal container with thread manufactured by drawing, drawing-and-ironing or impact forming from a metallic material, having a container main body consisting of a mouth part with a threaded part, a tapered shoulder part, a trunk part and a bottom part and maintaining a highly airtight condition with a cap screwed on,

characterized in that only one inwardly curving smooth annular recessed part and only one outwardly curving smooth annular protruded part is formed around an upper end of said smooth tapered shoulder part widening in a radial direction toward below from a lower end of said mouth part,

wherein a bead part for bending a lower end of said cap for engagement is formed in the vicinity of said lower end of said mouth part, the bead part being an annular groove having an almost trapezoidal cross-sectional configuration, and

wherein the inwardly curving smooth annular recessed part and the outwardly curving smooth annular protruded part has a radius of curvature in a range of approximately 0.5 mm to 5.0 mm and a common tangent line at an angle of inclination relative to a perpendicular reference line of approximately 35 to 60 degrees.

5. A metal container with thread manufactured by drawing, drawing-and-ironing or impact forming from a metallic material, having a container main body consisting of a mouth part with a threaded part, a tapered shoulder part, a trunk part and a bottom part and maintaining a highly airtight condition with a cap screwed on,

characterized in that only one inwardly curving smooth annular recessed part or only one inwardly curving smooth annular recessed part and only one outwardly curving smooth annular protruded part is formed around an upper end of said smooth tapered shoulder part widening in a radial direction toward below from a lower end of said mouth part,

wherein a bead part for bending a lower end of said cap for engagement is formed in the vicinity of said lower end of said mouth part, the bead part being an annular groove having an almost trapezoidal cross-sectional configuration, and

wherein said shoulder part being oriented at an angle with respect to a perpendicular line in a range of approximately 25 to 30 degrees, and the inwardly curving smooth annular recessed parts and/or the outwardly curving smooth annular protruded part has a radius of curvature as viewed in cross-section in a range of approximately 0.5 mm to 5.0 mm.

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